No, unlimited internet means use over GPRS (the 8520 doesn't have 3G)
However, it will not work on a Blackberry, and requires Blackberry Internet Service.
It will be an extra £5 per month (assuming your in the uk), and you should call virgin to discuss it.

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~Midnight Draven

"That's it then. Cancel the kitchen scraps for lepers and orphans, no more merciful beheadings... and call off Christmas."